Winter Weed Control: Russian olive
Russian olive (Elaeagnus angustifolia) is an invasive woody plant from western Asia. It is usually in the form of a small tree or large, multi-stemmed shrub. It invades pastures and riparian areas (stream and river banks), but is also very drought tolerant.
Russian olive is disrupting the native ecosystem. The small olive fruit is spread most commonly by starlings (another non-native species) and other wildlife under power lines and fences. However, the diversity of wildlife that use Russian olive for nesting and feed is less than with native plants. It is one of the most common invasive trees along ditches and the edge of fields in southern Idaho. Russian olive has become the fourth most common riparian tree in the Western U.S. It has also been shown to adversely affect native fisheries.
Russian olive readily produces sprouts or suckers from the stump or roots (that are close to the surface) after mechanical removal.
Integrated pest management options:
· Mechanical: Regular cultivation practices can “farm out” Russian olive. Otherwise, mechanical removal without goat browsing or herbicide treatment results in a worse problem from the re-growth.
· Cultural: None.
· Biological: Goats will browse on young Russian olive trees and may be used to help control re-growth after mechanical removal.
· Chemical: Frill cut (during the growing season), or cut-stump (year-round), or basal bark treatment prior to mechanical removal are effective application techniques (see previous posts on the techniques). Be sure the target weed and crop or landscape situations are listed on the product label. Always read and follow herbicide label directions.
Seeds can remain dormant for up to seven years, so a long-term control program is important. Combine different IPM options to help improve the effectiveness of your efforts.